Release Notes - C++ Driver - Version 3.5.0

The MongoDB C++ Driver Team is pleased to announce the availability of mongocxx-3.5.0. This release provides support for new features in MongoDB 4.2.

Please note that this version of mongocxx requires the MongoDB C driver 1.15.0 or higher.

See the MongoDB C++ Driver Manual and the Driver Installation Instructions for more details on downloading, installing, and using this driver.

The mongocxx 3.5.x series does not promise API or ABI stability across patch releases.

Please feel free to post any questions to the MongoDB community forum in the Drivers, ODMs, and Connectors category with the cxx-driver tag. Bug reports should be filed against the CXX project in the MongoDB JIRA. Your feedback on the C++11 driver is greatly appreciated.

The following are user-visible issues that have been resolved in 3.5.0 since the prior release:

Bug

• [CXX-1688] - MongoDB CXX driver does not compile with standard polyfill.
• [CXX-1689] - database::_create_collection is not using C++17-compatible string conversion.
• [CXX-1693] - Test with latest gcc
• [CXX-1720] - clang 7.0.1, Linux, c++14, libc++, ambiguous overload in change_stream.cpp
• [CXX-1769] - ChangeStream spec's Resumable Error definition is too broad
• [CXX-1901] - Building C++ driver from master fails to find cmake packages of C driver
• [CXX-1922] - scoped_bson_t::steal() doesn't clear _is_initialized flag
• [CXX-1938] - Catch does not guarantee running at least one test SECTION per TEST_CASE run

New Feature

• [CXX-1669] - Add an uninstall target
• [CXX-1678] - std::aligned_storage build failure with extra alignment
• [CXX-1681] - Implement Unified URI Options
• [CXX-1682] - Implement Convenient API for Transactions
• [CXX-1684] - Support mongos pinning for sharded transactions
• [CXX-1685] - Retryable Reads
• [CXX-1691] - Connections survive primary stepdown
• [CXX-1695] - Support sharded transactions recovery token
• [CXX-1696] - Aggregate command must be sent to a primary if it uses $out
• [CXX-1701] - Resync transactions tests to include test with session1 in APM expectations
• [CXX-1702] - Add database aggregate helper
• [CXX-1711] - Add CMake flags to build both shared and static libraries
• [CXX-1715] - Support 'startAfter' option to the $changeStream stage
• [CXX-1719] - Drivers should use majority write concern when retrying commitTransaction
• [CXX-1721] - Drivers should ignore batchSize=0 for aggregate with $out
• [CXX-1732] - Support Retryable Writes on by Default
• [CXX-1734] - Support postBatchResumeToken in change streams
• [CXX-1742] - Resync transaction spec tests for bulk write error reporting change
• [CXX-1743] - Add support for majority read concern level to Aggregation $out
• [CXX-1755] - Require retryable writes network error tests to run on mongos 4.2+
• [CXX-1756] - Add the ability to specify a pipeline to an update command
• [CXX-1759] - Document connection string and URI option precedence rules
• [CXX-1761] - Use runOn syntax to specify transaction test requirements
• [CXX-1771] - Allow applications to set maxTimeMS for commitTransaction
• [CXX-1805] - Operating System Removals/Updates for 4.2
• [CXX-1806] - Raise an actionable error message when retryWrites fails due to using an unsupported storage engine

Improvement

• [CXX-1532] - Demonstrate "pool" in thread-safety.md
• [CXX-1572] - Retryable writes should consider more errors retryable
• [CXX-1637] - Delete deprecated collection::replace_one overloads
• [CXX-1670] - Add test that reads ignore db/collection readConcern in transaction
• [CXX-1680] - COPYING and THIRD_PARTY_NOTICES should be installed to $PREFIX/share/doc/mongo-cxx-driver
• [CXX-1707] - Export targets for CMake project
• [CXX-1752] - Remove GitPython from calc_release_version.py
• [CXX-1783] - Don't send $readPreference to standalone servers
• [CXX-1790] - Test MongoDB 4.2 in Evergreen
• [CXX-1795] - Use runOn syntax to specify CRUD test requirements
• [CXX-1820] - Deprecation warning on mongoc_uri_get_ssl
• [CXX-1834] - Make pipeline extensible
• [CXX-1899] - Typos in install guide